Khaki Campbells - adult feathers?

Short memory here. We have two Khaki Campbell drakes and two "hens". The drakes about 5 months. The hens are 2 months and just starting to lose their feathers. I am trying to remember at what age we could distinguish the drakes from the hens. When the "drake" markings started showing up. The hens have been molting for about a week now. Seems to me the drake feathers showed up shortly after they started molting. So that maybe I should be able to seem distinguishing marks by now? I know it took about another month until their heads started to change color substantially.

The two Khaki hens are in the foreground. Only one of the quacks like a hen should, so am anxiously anticipating the distinguishing feathers coming in. They were supposed to be sexed birds.

Yeah, eventually, but their heads took much longer to develop that dark color than the feathers that changed in the wing area or a little below there. Don't know what to expect from hens, since the first two "hens" weren't hens at all. The drakes I could tell they were drakes from changes in feathers before their heads turned.

One of the is 'iffy' on voice. Rarely get clear quack when picked up, but sometimes so not sure. My other hens have been much more vocal, but this one seems to give off clear quack, but rarely. Weird duck.